• Korean Journal of Veterinary Research
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• v.30 no.3
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• pp.297-307
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• 1990

To establish an agar-gel immunodiffusion (AGID) test for detection of antibodies to Aujeszky's disease virus(ADV) in swine, the precipitating antigens were prepared by four procedures using the Aujeszky's disease virus, NYJ-1-87 strain isolated from the affected piglets in Korea. The optimal condition for AGID test and the properties of the antigens were investigated. To determine the optimal concentration of antigens, four antigens were experimentally prepared by concentrating the viral fluids by 1/30 to 1/200. It was proved that the antigen precipitated with ammonium sulfate at concentration of 1/100 was the most efficient to detect ADV antibodies by AGID test. When the relationship between the concentration of the antigens and the size of precipitating in radial immunodiffusion test was investigated, a high correlation coefficiency at r=0.95 (y=0.23x+23.4) was estimated, In study on the effects of various buffered salt solutions and agars on the sensitivity of AGID test by using the experimental ADV antigens, it was found that 0.05M tris buffer without sodium chloride at pH 7.2 induced the most distinctive precipitating lines, and that there was no significant differences in the sensitivity between the agarose and Noble's special agar. When the efficiency of AGID test was compared with serum neutralization(SN) test, the sensitivity of AGID test was 100% in SN titer over 1 : 16, 91.7% in SN titer of 1 : 8 and 57.1% in SN titer of 1 : 4. The specificity of AGID test compared with the sera with SN titer under 1 : 2 was 98.4%. Protein analysis of the antigens by SDS-PAGE indicated that antigen I and antigen III showed a specific band of polypeptides with molecular weight of 116 K in comparison with the control antigen. Antigen IV, treated with tween-80 and ammonium sulfate, revealed specific polypeptides bands at the molecular weights 45K, 98K and 150 K.

• Biomedical Science Letters
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• v.8 no.4
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• pp.269-273
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• 2002

Dengue fever (DF) is an acute febrile illness caused by dengue viruses in the family Flaviviridae, genus Flavivirus. DF has so far posed any problem in Korea, however it has been recently believed to be associated with oversea's traveler infected with dengue virus. Antibody titers of sera from DF patients against dengue virus were measured by indirect immunofluorescence assay (IFA) and plaque reduction neutralization test (PRNT), including the haematologic test. Three of patients with DF showed highly fluorescent and neutralizing antibody titers by IFA and PRNT assay. Two of them showed higher, remarkably. Meanwhile, one of them was tested and resulted in severe tirombocytopenia, elevated serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) activities as well as mild leucopenia, increased monocytes and basophils and depressed lymphocytes in haematological differential count.

• Laboratory Medicine Online
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• v.1 no.1
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• pp.64-66
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• 2011

Anti-Sd^a is of no clinical significance, because it rarely causes hemolytic transfusion reactions. Even when its presence is suspected during antibody screening test, further identification of the antibody is usually not performed. We experienced a case of anti-Sd^a in 73 yr-old male patient showing mixed field agglutination by microcolumn agglutination. Antibody specificity could not be identified by conventional antibody identification test, and it was proven to be anti-Sd^a by urine neutralization test. In spite of its little clinical significance, it may give incompatible crossmatching results reacting with Sd^a antigen, which occurs at a high frequency in general population. When incompatible crossmatch results arising from anti-Sd^a are suspected, the problem may be solved by using the urine-neutralized serum of in crossmatching test.

• Journal of Veterinary Clinics
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• v.17 no.1
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• pp.45-51
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• 2000

Sera from 425 Korean native and 203 Holstein cattle were collected from October 1994 to September 1995 from dairy farms and slaughterhouses in Chonnam province to study the exposure rate to bovine respiratory syncytial virus(BRSV). Serum antibody titers against BRSV were measured by neutralization test, and results were as follows: Overall prevalence of seropositive cattle to BRSV were 74.5%, and the exposure rate to BRSV was higher among the Holstein (77.3%) than among the Korean native cattle(73.2%). The serum antibody titers against BRSV ranged from 1:2~$\geq$1:256 in both species. Among Korean native cattle, the most frequent serum antibody titer was 1:4 against BRSV(19.3%), while only 1.4% of seropositive cattle had serum titer of $\geq$1: 256. Among Holstein cattle, 22.7% of examined cattle contained serum titer of 1:8, while 1.5% of seropositive cattle showed $\geq$ 1:256. Antibody titers against BRSV were higher among males than females in both Holstein (82.1% vs. 73.1%) and Korean native (74.5% vs. 69.2%) cattle. Prevalence of seropositive cattle by age in both species were evenly distributed, although the highest number (76.9%) of seropositive were at the age of 3 in Korean native cattle, while 83.5% of seropositive Holstein cattle were of 2 years old. The lowest seropositive rate was observed in cattle of less than 1 year old(25.0%). Seasonal occurrunce of BRSV was the highest in spring season in both Holstein (86.6%) and Korean native (81.0%) cattle (P<0.05).

• Journal of Veterinary Science
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• v.22 no.4
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• pp.56.1-56.10
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• 2021

Background: Fluorescent antibody virus neutralization (FAVN) test is a standard assay for quantifying rabies virus-neutralizing antibody (VNA) in serum. However, a safer rabies virus (RABV) should be used in the FAVN assay. There is a need for a new method that is economical and time-saving by eliminating the immunostaining step. Objectives: We aimed to improve the traditional FAVN method by rescuing and characterizing a new recombinant RABV expressing green fluorescent protein (GFP). Methods: A new recombinant RABV expressing GFP designated as ERAGS-GFP was rescued using a reverse genetic system. Immuno-fluorescence assay, peroxidase-linked assay, electron microscopy and reverse transcription polymerase chain reaction were performed to confirm the recombinant ERAGS-GFP virus as a RABV expressing the GFP gene. The safety of ERAGS-GFP was evaluated in 4-week-old mice. The rabies VNA titers were measured and compared with conventional FAVN and FAVN-GFP tests using VERO cells. Results: The virus propagated in VERO cells was confirmed as RABV expressing GFP. The ERAGS-GFP showed the highest titer (10^8.0 TCID₅₀/mL) in VERO cells at 5 days post-inoculation, and GFP expression persisted until passage 30. The body weight of 4-week-old mice inoculated intracranially with ERAGS-GFP continued to increase and the survival rate was 100%. In 62 dog sera, the FAVN-GFP result was significantly correlated with that of conventional FAVN (r = 0.95). Conclusions: We constructed ERAGS-GFP, which could replace the challenge virus standard-11 strain used in FAVN test.

• Journal of Life Science
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• v.19 no.9
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• pp.1304-1308
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• 2009

To investigate the infection patterns of porcine epidemic diarrhea virus (PEDV) in Korean pig farms, a total of 4,768 swine sera samples from 159 pig farms were taken twice, in June (n=82) and October (n=77) in 2007. In each farm selected for the survey, 10 samples from breeding pigs and 4 from each of the 5 age groups (30, 60, 90, 120, and 150 days) were taken, and all serum samples were tested for PEDV by the serum neutralization test. The overall seroprevalence was 62.6% (2,983/4,768), with the highest prevalence in breeding pigs (93.5%, 1,485/1,589). The prevalence showed an increasing trend with increasing age (30.8, 27.2, 44.7, 61.6, and 71.2% respectively in the 30, 60, 90, 120, and 150 days age groups) (p<0.0001 for $x^2$ trend test). The association between age and PEDV prevalence was similar in both surveys, indicating that the infection of PEDV seemed to be occurring repeatedly in the farms surveyed. This inference could also be explained by the fact that prevalence in sows was very high despite low vaccination coverage, as they are continuously exposed to PEDV in potentially infected farms for a longer period. Based on the neutralizing antibody levels in sows and growing pigs, the majority of farms (91.8%, n=146 farms) were endemically infected with PEDV, and most of pigs seemed to be intensively infected with PEDV at around early growth (41.8%) and weaning (31.5%). On the other hand, serum neutralizing antibodies were not detected in pigs older than 30 days of age in farms classified as having no PEDV infection (n=13 farms), indicating the level of maternal antibody against PEDV is decreased on a non-detectable level before the piglet is 60 days old in the field situation. The results indicated that most farms surveyed in 2007 were affected with endemic PEDV infection. Therefore, a national monitoring and control program for the endemic type PEDV infection needs further attention.

• Journal of Veterinary Science
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• v.21 no.4
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• pp.63.1-63.9
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• 2020

Background: Canine adenovirus type 2 (CAV-2) induces infectious laryngotracheitis in members of the family Canidae, including dogs. To date, no ELISA kits specific for CAV-2 antibody have been commercialized for dogs in Korea. Objectives: We aimed to develop new indirect enzyme-linked immunosorbent assay (I-ELISA) to perform rapid, accurate serological surveys of CAV-2 in dog serum samples. Methods: In total, 165 serum samples were collected from dogs residing in Chungbuk and Gyeongbuk provinces between 2016 and 2018. The Korean CAV-2, named the APQA1701-40P strain, was propagated in Madin-Darby canine kidney cells and purified in an anion-exchange chromatography column for use as an antigen for I-ELISA. The virus-neutralizing antibody titers of CAV-2 in the dog sera were measured by virus neutralization (VN) test. Results: We compared the results obtained between the VN and new I-ELISA tests. The sensitivity, specificity, and accuracy of new I-ELISA were 98.6%, 86.4% and 97.0% compared with VN test, respectively. New I-ELISA was significantly correlated with VN (r = 0.91). Conclusions: These results indicate that new I-ELISA is useful for sero-surveillance of CAV-2 in dog serum.

• Microbiology and Biotechnology Letters
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• v.46 no.3
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• pp.269-276
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• 2018

Rabies virus (RABV)-specific antibodies in animals and humans are measured using standard methods such as fluorescent antibody virus neutralization (FAVN) tests and rapid fluorescent focus inhibition tests, which are based on cell culture systems. An alternative assay that is safe and easy to perform is required for rapid sero-surveillance following mass vaccination of animals. Two purified monoclonal antibodies (4G36 and B2H17) against RABV were selected as capture and detection antibodies, respectively. A genetically modified RABV, the ERAGS strain, was propagated and concentrated by polyethylene glycol precipitation. Optimal conditions for the RABV antigen, antibodies, and serum dilution for a blocking enzymelinked immune sorbent assay (B-ELISA) were established. We evaluated the sensitivity, specificity, and accuracy of the B-ELISA using serum samples from 138 dogs, 71 raccoon dogs, and 25 cats. The B-ELISA showed a diagnostic sensitivity of 95.8-96.3%, specificity of 91.3-100%, and accuracy of 96.0-97.2% compared to the FAVN test. These results suggest that the B-ELISA is useful for sero-surveillance of RABV in dogs, raccoon dogs, and cats.

• Korean Journal of Veterinary Service
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• v.32 no.4
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• pp.293-298
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• 2009

Porcine respiratory coronavirus (PRCV) is antigenically related to transmissible gastroenteritis virus (TGEV). Differential serological diagnosis between PRCV and TGEV infection is not possible with the classical sero-neutralization test. Infection with PRCV or TGEV induces antibodies which neutralize both viruses to the same titer. However, the enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) can differentiate between PRCV and TGEV infection. This study was carried out to investigate the prevalence of PRCV infection of swine in Gyeongnam province. A total of 391 serum samples from 37 herds in Gyeongnam were examined for antibody to PRCV using blocking ELISA. All serum samples were collected from 130- to 150-day-old pigs between August and December 2006. By ELISA, 182 out of 391 sera tested (46.5%) and 29 out of 37 sample herds (78.4%) were positive against PRCV. Our data suggested that seropositive herds for PRCV are distributed diffusely throughout Gyeongnam. The PCR methods were established to diagnose PRCV spike protein (S) gene. PCR were conducted to identify the PRCV genome against 150 pigs in PRCV antibody positive herds.

• Korean Journal of Veterinary Research
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• v.28 no.1
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• pp.89-97
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• 1988

Twenty-eight porcine rotavirus were isolated from piglets with diarrhoea in chonnam province. According to the age, 41 to 60 day old pigs showed the highest isolation frequency among the post weaning pigs. The characteristics of the field isolates were determined by electronmicroscopy(EM), immunofluorescent assay(FA), and electrophoretic migration patterns of the genome profiles. Some of the isolates showed remarkable haemagglutination activity against rabbit and dog erythrocytes, ranged from 4 to 2848, respectively. At least 3 serotypes of porcine rotavirus were recognized by serum neutralization test using serotype specific rotavirus hyperimmune sera.